Apparatus for folding flexible materials



United States Patent Inventor App]. No.

Filed Patented Assignee Priority Kurt Hoffmann Heidelberg, Germany Feb.10, 1969 Dec. 29, 1970 Chrobok-Hoffmann K. G.

Eppelheim, near Heidelberg, Germany Feb. 26, 1968 Germany APPARATUS FORFOLDING FLEXIBLE MATERIALS 9 Claims, 7 Drawing Figs.

[52] US. Cl 270/61 [51] Int. Cl B65h 45/00 [50] Field of Search 270/61[56] References Cited UNITED STATES PATENTS 3,024,019 3/1962 Ladenburger270/61 3,148,874 9/1964 Forthmann, Jr 270/61 Primary Examiner-Eugene R.Capozio Assistant Examiner-Paul V. Williams AtzorneysFrancis D. Stephensand Hugo Huettig, Jr.

ABSTRACT: Pairs of vertically movable flat plates having die openingsare used to fold the edges of flexible materials.

upper portion containing a press plate, a press plunger, and

means for folding the material and ejection of the finished piece. Thisinvention simplifies the construction and considerably improves theoperation of the plural operational steps of heretofore usedfoldingapparatus. In the heretofore used folding apparatuses which fold inoneoperational cycle and upon which -this invention is an improvement,the two spaced plates which form the lower portion of the apparatus arerigidly connected to each other while the press plate can be movedvertically through a die opening in the upper plate of the lower toolportion. The upper portion also is composed of two spaced plates whichare rigidly connected to each other. The plunger. below the lower plateof the upper portion, is rigidly connected to the folding knife formingthe outer edge. A plate joined to the plunger can be moved verticallyfor pressing down on and holding the workpiece in place. The foldingstep takes'place during the lowering of the plunger in the lower portionof the apparatus and at the same time the plunger, during itsupwardreturn movement to its original position, and by lifting the upperportion ejects the finished workpiece. Since this apparatusoperates witha special apparatus for holding the workpiece in place and with afolding knife which surrounds the clamping apparatus, it is possible tofold only workpieces up to a certain size. The use of a folding knifecan cause disruptions, especially when glue is used.

The object of this invention is to reduce substantially the cost of thefolding apparatus and simultaneously to improve upon its operation bymaking it adaptable to multiple use for all usual and conventionalworkpiece sizes.

In general, this object is obtained in this invention in that the pressplate is rigidly connected with the lower plate of the lower portionofthe apparatus and can bemoved through a die opening having a recessedrim formed in the upper plate which is moved relative to the lower plateagainst spring pressure. The press plunger is rigidly connected to theplunger holding plate which is positioned so that it can be movedvertically between the lower and upper plates of the upper portion whichare rigidly connected to each other, and with the plunger holding platebeing urged to is upper position by springs. and with the use ofclamping means that can be released in the lower position by the plungerholding plate so that the pressplunger can slide through the die openingin the lower plate of the upper portion. Consequently, in thisinvention, the press plate, in contrast to the heretofore usedapparatus, is rigidly joined to the lower portion of the apparatus, andin which the upperplate of the lower portion is movable. The pressplunger within the upper portion of the apparatus is also movable, ascontrasted to the press plunger rigidly connected in the upper portionof the heretofore used apparatus.

As contrasted to the heretofore used apparatus, this invention results.in a simplified construction and an improved operating technique. Thisinvention does not require a special folding knife as heretofore used.In this invention, there is instead attached to the lower side of thelower plate of the upper portion a folding plate which fits into arecessed rim in the upper plate of the lower portion. The folding stepis improved in that the inner side edges of the folding plate extend ina curve to its bottom and to the lower surface of the completelyretracted plunger. This arrangement makes it possible to size the pressplate as well as thepress plunger and folding plate as small as possibleand to use them for small workpieces often encountered in this work.Also, the elimination of the folding 75 knife avoids any disruption ofthe apparatus.

In this invention, posts, pins or pegs are attached to the lower plateof the lower portion which are slidable-in bores of the upper plate andwhose upper ends are conical and extend beyond the upper plate throughbores through the lower plate .of the upper portion and act inconjunction with the releasable clamping and fixing device of the upperportion of the apparatus. This control clamping device. for the plungerholding plate has a further feature in that two. sliders are arrangedon" the narrow sides of the upper portion and which are slidable inguide members which are fixed to the lower plate of the upper portion.The head of each slider facing the plunger holding plate has a nosewhich can extend over the plunger holding plate. Each slider is held inits clamping position by a pressure spring. Also, the head of eachslider is beveled forming a surface which the plunger holding plateengages during its downward movement so that the sliders are pushedoutwardly. Bores extend through the sliders and guide members throughwhich the conical ends of the guide posts of the lower portion canextend and engage and force the sliders into their release positions sothat the plunger holding plate can be released. Finally, the sliders areprovided with a stop on their outer ends which restrict their engagedposition.

The surface of the press plate can be provided with the conventionalstampings for ornamenting the surface and serrating the edges of theworkpiece. By means of this, it is possible that very small workpiecescan be provided with fluted or serrated edges.

The means by which the objects of this invention are obtained aredescribed more fully with reference to the accompanying drawings inwhich: 7

FIG. I is a longitudinal cross-sectional view through the apparatus astaken on line H of FIG. 2 and in which the left side of the FIG. showsthe apparatus in open position and the right side in closed position; v

FIG. 2 is a cross-sectional view along-the line ll-II in FIG. 1;

FIG. 3 is a cross-sectional view taken on the line Ill-III of FIG. 1;

FIG. 4 is a schematic plan view of the various steps taken in thefolding of the edges of a workpiece;

FIG. 5 is a cross-sectional view taken on the line V-V of FIG. 4; g

FIG. 6 is a similar view of the intermediate step with the edgesstanding vertically; and

FIG. 7 is a cross-sectional view taken on the line VII-VII of FIG. 4.

The folding apparatus of this invention has two main portions, namely,the lower portion and the'upper portion.

' The lower portion is composed of a basev plate 1 on which the guideposts 2 and 3 for the guideplate 4 are fixedly mounted. Guide posts 2are positioned approximately at the four outer corners of plates 1 and 4and are at the same time used as the bearing members for compressionsprings 5. The

posts 2 are made as threaded bolts for the purpose of holding. springs 5on the underside of guide plate 4 and are inserted through the springsand screwed into the base plate 1. Guide posts 3 extend upwardly andsomewhat beyond the upper guide plate 4. The posts have conical upperends 6. Threaded holes 7 are positioned on the outer corners of plate 1for attaching this plate to a machine table. However, a dovetail jointcan be used for attaching plate 1 instead of using threaded holes 7.Fixed to the center of the upper surface of plate 1 is a press plate 8whose surface corresponds to the'shape of the workpiece that is to befolded. A die opening 9 is in the upper guide plate 4 and into whichplate 8 extends when plate 4 is moved against the pressure of springs 5toward plate 1. A recessed rim 10 which is larger than the size ofopening 9 is used for placing the workpiece to be folded.

The upper portion of the apparatus is composed of two plates which arethe lower plate 11 and the upper plate 12 fixed to each other by fourbolts 13 positioned at the corners of plates 11 and 12. Folding plate144 is, fastened to the lower side of lower plate 11 and plate 14has asliding, fit into the recessed rim, 10 in the guide plate 4 in the lowerportion.

Plunger holding plate 15 which is movable up and down is positionedbetween the two plates 11 and 12 in the upper portion imam is'guided inthe upper plate 12 by means of posts 16. Two'posts a'reshown in thedrawing. Compression springs 17 ,are positioned'on the four corners ofthe plunger holding plate 15 which urge plate '15 upwardly against upperplate 12. F Plunger 18 is fastenedto the lower side of plunger holdingplate 15 and is moved up'and down along with plunger holding plate 15and is slidably guidedthrough an opening 19 in lower plate 11. Plunger18 can be made in one piece. However, for special production techniques,its lower part 20 can be made of a special piece which is attached tothe lower surface of the actual plunger 18. In order to hold plungerholding plate 15 in its lower position against the pull of spring 17, areleasable clamping device is positioned on each outer side,respectively, on the upper surfaces of plate 11 and between plates 11and 12 and also opposite guide posts 16. In plane view, these clampingdevices are on the narrow sides of the rectangular outline of themachine. These clamping devices hold plunger holding plate 15 in itslower position. Each of these clamping devices is composed of a slider21 which can be reciprocated toward and away from holding plate 15 andwhich slider is held in a guide member 22 fixed to plate 11. The end ofslider 21 facing plunger plate 15 has a head 23. This head has a nose 24which extends over the edge of plate 15 when the plate is lowered andwhich holds the plate 15 down against the pull of spring 17. The slideris held in clamping position by a spring 25 which bears against guidemember 22 and head 23 and urges the head toward plunger holding plate15. A stop pin 26 is inserted through the outer end of slider 21 forrestricting the forward movement of slider 21'.

In the right-half side of FIG. 1 and in FIG. 2, the plunger holdingplate 15 is shown in its lowered position in which it is held by thenose 24 on slider 21. The left-half side of FIG. 1 shows'the holdingplate in its released upper position in which it is forced upwardly bysprings 17 into contact with upper plate 12. Bores 27 and 28 in slider21 and guide member 22, respectively, are entered by the conical ends 6of guide posts 3 when the upper portion of the apparatus is moved towardthe lower portion. The guide posts 3 are then extended through bores 27and 28 so that their conical ends 6 engage and push r the slidersoutwardly whereby the noses 24 are released from the plunger holdingplate 15 which is then quickly moved upwardly by springs 17. Post 29attached to the upper side of plate 12 in the upper portion is used tohold the upper portion in the apparatus.

In operation, the blank workpiece, as, for example, a stamped out pieceof leather, such as shown in FIG. 5, is placed with its front sidedownwardly in the open machine, as in the left side of FIG. 1, and inthe recessed rim of guide plate 4. Then the upper portion of the tool islowered and guided by posts 3 toward guide plate 4. This brings theplunger 18. 20 into contact with the workpiece and presses the same intothe die opening 9. When the plunger 18, 20 enters the die opening 9, theedges of the workpiece are turned up all around the workpiece, as shownin FIG. 6. In the'lowermost position of the plunger 18, 20 in which theworkpiece has reached the bottom of die opening 9 and when plunger 18,20 is directly on top of the workpiece, as shown in the right half ofFIG. I, the conical ends 6 of posts 3 release the control clampingdevice 21 which lies between plates 11 and 12 of the upper portion.Because'of the pressure of springs 17, the plunger holding plate movesrapidly upward until it reaches a stop on the underside ofupper plate12. In this manner, the plunger 18, is pulled out of die opening 9. Thisis the position as shown in the left side of FIG. 1. At this time, theworkpiece is still on the bottom of die opening 9 with the folded edgesextending vertically at right angles. as shown in FIG. 6. The entireupper portion of the tool is moved at this point further downwardly bymotor means. not shown. whereby the folding plate 14 enters the recessedrim l0 and bears on the bottom of the rim. The upper portion is loweredfurther and pushes guide plate 4 downwardly against the pressure ofsprings 5. During this time. plate 4 pushes downwardly around pressplate 8 which enters die opening 9 so that the workpiece enters theinterior of the folding plate 14. During this step. the upright edgesofthe workpiece enter guide plate 4 which has a curved corner between itsinner .side edges and the bottom .of the fully retracted plunger 18, 20so that the upstandingedges. are completely folded over and pressedtight; as shown in FIG.. '7 and in the right side of FIG..,4.. Since theedges of the work;

piece have been coated with glue before the workpiece was placed in theapparatus, these edges become tightly glued during the last pressing ofthe workpiece. When the workpiece edges are to be serrated, then thesurfaceof the press plate 8 has to be provided with a correspondingprofile aside from its outer edges. This makes it possible to fold andserrate the edges of the workpiece in one work step. After folding and,if desired, simultaneously serrating the edges of the workpiece, theworkpiece lies within the folding plate 14. Then the workpiece iscarried along during a further lifting of the upper portion until theupper ends of the guide posts 16 joined to plunger holding plate 15 comeinto contact with a stop, not shown, in the apparatus. Then the plungerholding plate 15 is pressed downwardly against the pressure of springs17 during a further lifting of the upper portion. During this motion,the outer edges of plunger holding plate 15 engage the beveled surfaces30 above the noses 24 on the sliders 21 and thus force the slidersoutwardly during a further movement until the plunger holding plate 15comes into contact with the upper surface of lower plate 11 of the upperportion and the noses 24, because of springs 25, clamp over the edges ofthe plunger holding plate 15. The plunger 18, 20, while this movement istaking place, comes out of folding plate 14 whereby the folded andfinished workpiece is ejected downwardly.

I claim:

1. An apparatus for folding flexible materials such as leather, textilesand corresponding synthetic materials comprising a lower portion havinga lower plate I spaced from an upper plate 4 having a die opening 9therein surrounded by a recessed rim 10, a press plate 8 mounted on saidlower plate 1 and movable through said die opening 9, spring means 5 formovably supporting said upper plate 4; an upper portion having a lowerplate 11 and an upper plate 12, a plunger holding plate 15 verticallymovable between the lower plate 11 and the upper plate 12, spring means17 for urging said holding plate 15 toward said upper plate 12, clampingmeans 21 for clamping said holding plate 15 on said lower plate 11, anda press plunger 18 secured to said holding plate 15 and movable by saidholding plate 15 through said die opening 19 in said lower plate 11.

2. An apparatus as in claim 1, further comprising a folding plate 14secured to the underside of said lower plate 11 and surrounding saidpress plunger 18 and fittable in said recessed rim 10.

3. An apparatus as in claim 2, said folding plate having a curved innerside edge extending from the lower face of said folding plate to thelower face of the press plunger 18 when in fully retracted position.

4. An apparatus as in claim 3, further comprising posts 3 joined to saidlower plate 1 and extending through bores in said upper plate 4 and saidlower plate 11, and conical end means 6 on said posts for actuating saidclamping means 21.

5. An apparatus as in claim 4, saidclamping means 21 comprising a guidepiece 22 secured to said lower plate 11, a slide movable through saidguide piece;a head 23 on said slide and nose means 24 on said head forreleasably clamping said plunger holding plate 15 to said lower plate11.

6. An apparatus as in claim 5, further comprising spring means 25between said guide piece 22 and said slide for urging said slide toclamping position on said plunger holding plate.

7. An apparatus as in claim6, further comprising diagonally slantedsurface means 30 on said head 23 engageable by said plunger holdingplate 15 for releasing said slide from said clamping position duringdownward movement of said plunger holding plate.

9. An apparatus as in claim 8, funther comprising fluted surface meanson said press plate 8 for folding the serrated edge of a workpiece.

